“More than 20 billion tons of concrete is produced around the world every year”–to fuel the building boom in cities as more and more people globally move to urban areas.
But, all that concrete has a large environmental cost. “Cement, the main ingredient in concrete, creates 5% of global carbon emissions.”
Concrete is “sand and gravel held together with cement.” The Romans “used a mixture of volcanic ash and lime to make concrete.” And, Roman concrete structures have stood for thousands of years.
Now, engineers working in the United States have created a new material that could replace cement in the production of concrete. They have used fly ash (“fine particles formed when coal is burned in power plants”); fly ash is similar to volcanic ash. Using statistical analysis, the engineers determined the best ratio for combining fly ash with other ingredients and the optimum type of fly ash to use.
Tests are showing that concrete made from this fly ash binder is “just as strong as conventional cement-based concrete after seven days.”
More testing awaits, but the new material and its “reduced CO2 footprint” may provide a low-cost, more environmentally-friendly binder for future building. Plus, the use of fly ash reduces waste from coal-fired power plants.
Read the article (Prachi Patel, Quartz, June 26, 2018).